Brightness Scaling of High Power Laser Diode Bars

High power laser diode bars used in pumping units of solid state or fibre lasers or as a direct source in laser diode systems have in the last years become more and more important for industrial laser applications such as welding, brazing, hardening or marking. Increasing the brightness of the laser diode source offers the possibility to use fibres with smaller numerical apertures and smaller core diameters, and therefore to increase the brightness of the laser beam emitted by the laser system used for the materials processing step. With Bookham´s new very high brightness (VHB) devices described in this paper, the next significant increase in brightness by a factor of up to 4 depending on the beam shaping technique has been achieved.